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LCQ8: Pneumococcal conjugate vaccine

     Following is a question by the Hon Alan Leong and a written reply by the Secretary for Food and Health, Dr York Chow, in the Legislative Council today (January 19):


     Recently there has been a spate of local cases of invasive pneumococcal infection among children and two of them were in critical condition at one time.  Some parents have pointed out that the Government is duty-bound to examine the current policy at all times and provide children with the necessary preventive vaccines, so as to provide them with adequate health protection.  In this connection, will the Government inform this Council:

(a) of the average number of isolates of serotype 3 Streptococcus pneumoniae recorded in Hong Kong in each of the years from 2007 to 2010; whether the cases of infection caused by this type of pneumococcus bacterium have shown an upward trend, and whether there is a potential risk of an outbreak in the community;

(b) given that invasive pneumococcal diseases are not statutory notifiable infectious diseases at present, and that the Centre for Health Protection (CHP) under the Department of Health had only confirmed and made public the serotype 3 Streptococcus pneumoniae infection in question more than one month after occurrence of the aforesaid cases, of the current notification mechanism for pneumococcal infections; whether the authorities have plans to review the mechanism in future;

(c) whether the authorities have collected information on the respective use of 7-, 10- and 13-valent Pneumococcal Conjugate Vaccine (PCV) by various countries for protection against pneumococcus bacteria; if so, the countries currently using 7-, 10- and 13-valent PCVs (set out in table form); if not, of the reasons for that; and

(d) what criteria have been adopted by the Scientific Committee on Vaccine Preventable Diseases under CHP in introducing vaccines against pneumococcus bacteria; whether the authorities will make reference to the practices of the United Kingdom, the United States or other places in Asia; if so, of the details; if not, the reasons for that?



     Pneumococcus may cause invasive pneumococcal diseases such as bacteraemic pneumonia, meningitis and septicaemia.  More than 90 serotypes of pneumococcus have been identified so far.  Three types of pneumococcal conjugate vaccine (PCV) are available on the market for infant vaccination which respectively confer protection against seven serotypes (7-valent PCV), 10 serotypes (10-valent PCV) and 13 serotypes (13-valent PCV) of pneumococcus.  Currently, neither the World Health Organisation nor the Scientific Committee on Vaccine Preventable Diseases (SCVPD) under the Centre for Health Protection has made any recommendation on which PCV is to be used as a priority.

     Our reply to the four parts of the question is as follows:

(a)  On average, there are about 20 to 30 cases of serotype 3 invasive pneumococcal infection in Hong Kong each year.  According to the laboratory surveillance system on pneumococcus bacteria, 27, 21, 25 and 31 isolates of serotype 3 pneumococcus bacteria have been recorded in each of the years from 2007 to 2010 (as at December 16) respectively.  As the surveillance system did not cover all microbiological laboratories in public and private hospitals prior to 2009, the aforementioned figures for 2007 and 2008 might have been lower than the actual number of isolates.

     The Department of Health (DH) has investigated into the four cases of children with serotype 3 pneumococcal infections recorded in November and December last year.  It was revealed that there was no epidemiological linkage among these cases and their family contacts were not infected.  Laboratory analysis also showed that these cases were of different genetic makeup.  Hence, they did not constitute an outbreak from the same clone of organism.

(b)  From the perspective of public health, an analysis of the trend of various serotypes of pneumococcus is of considerable importance for understanding the overall epidemiological profiles of pneumococcus and for deciding which vaccine is to be used.  In this connection, DH has set up a laboratory surveillance system for analysis and surveillance on invasive pneumococcal infections.  This laboratory surveillance system now covers all the microbiology laboratories in public and private hospitals.

     DH received a report from Queen Mary Hospital on December 9 on three cases of children with invasive pneumococcal infection caused by serotype 3 pneumococcus.  Under the special circumstance that these might have been suspected cluster cases, an investigation was launched immediately and a press release was issued in the evening on the same day to inform the public of the preliminary investigation findings.  When notified of another case of a child with serotype 3 pneumococcal infection on December 16, DH also issued a press release on the same day.

     Pneumococcus is commonly and widely found in the community (as in the case of influenza), and the releasing of statistics on individual infection cases is not of particular significance to the overall control and prevention of the disease.  Therefore, in general, DH does not make announcements on individual cases of invasive pneumococcal diseases.  DH will keep the surveillance system and its functions under constant review and provide regular updates on invasive pneumococcal infections.  A recent example is the publication of the bi-weekly "Communicable Diseases Watch" (Number 22 and Number 27 in 2010) by the Centre for Health Protection.

(c)  DH has all along kept in view the use of PCV overseas.  At present, most of Hong Kong's neighbouring countries and territories have not included PCV in their childhood immunisation programmes (CIPs).  In the countries and territories that have included PCV in their CIPs, 7-valent PCV, 10-valent PCV and 13-valent PCV have been used.  Details are shown in annex.

(d)  In making recommendations on pneumococcal vaccination, SCVPD will take into account a number of scientific factors, including:

- local epidemiology (such as incidence and mortality rates);
- changes in the serotype replacement of pneumococcus;
- disease burden;
- the safety, efficacy, side effects and cost effectiveness of the vaccine;
- supply in the market; and
- the acceptance of the vaccine by the public, etc.

     Owing to a range of factors, the type of vaccine eventually chosen by a country or territory may vary.  DH will take into account the recommendations of SCVPD for procurement of a suitable vaccine to safeguard public health.

Ends/Wednesday, January 19, 2011
Issued at HKT 13:00


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